In United Kingdom Pat. No. 1,488,861, there is described and illustrated a hydraulically or pneumatically operated railway switch machine in which there are separate fluid actuators for switching the movable parts or points of the rails and for locking the movable parts or points of the rails in their respective switched positions. In the past, the movable parts or points of the rails were locked except when switching operation was taking place, so that the switch points could not be trailed without damaging the switch machine and/or the mechanical linkage which connected the switch machine to the movable points of the rails. That is to say, a railway vehicle approaching the switch points on a given route in a converging direction relative to the alternative route settable by the switch machine cannot pass through the points when they are switched to the alternative route without forcing the points to switch to the vehicle's route with consequential damage to the machine or the linkage due to the points being locked to provide passage on the alternative route. It will be appreciated that switch machines which are trailable, at least at low speed are known; but it is also well recognized that damage is caused to switch machines that are not designed for trailing operation. However, the present invention provides a solution to this problem by adapting an untrailable switch machine to a trailable one which can be trailed without any resultant damage.